Epidemiology
Lead exposure occurs through inhalation and ingestion.[4]
In the US and other developed countries, removal of lead from petrol dramatically decreased the population-wide exposure to lead from this source. Closure of lead smelters in the US has removed the major point-source exposure. Decreases in airborne lead in the US resulted in a decline in blood lead levels for people ages 1 to 74 years, from 0.6 micromoles/L (12.8 micrograms/dL) in 1976 to 1980 to 0.1 micromoles/L (2.8 micrograms/dL) in 1991.[5] Airborne lead continues to be a problem in the very few countries that still use leaded petrol.
Lead is a cumulative toxicant with very prolonged residence in bone. Because multiple real and potential sources of lead exposure exist throughout life, evaluating sources of exposure requires evaluation of lifelong events, particularly in older adults. Patients living in poverty are more likely to live in old and poorly maintained housing with deteriorating paint surfaces, and therefore have an increased risk of lead exposure.[6]
Lead exposure in children
In the US and other developed countries, the major risk to children is from lead-based paints and soil and dust contaminated with lead-based paint. Secondary sources include lead jewellery, toys, and other lead items. Lead levels in children usually increase during the period of hand-to-mouth activity (ages 9-36 months) due to the nature of these sources. Blood lead levels in children peak at age 18 to 24 months.[6] Blood lead surveillance is a useful tool.[7] CDC: childhood lead poisoning prevention program Opens in new window; Public Health England: lead exposure in children surveillance reports Opens in new window
In England, 35 cases of lead exposure in children were notified in 2020.[8] The number of cases detected was much lower than the expected incidence of lead exposure based on international population survey data. Cases were typically 1 to 4 years of age, male, and resident in more deprived areas; the median blood lead concentration of cases was 0.7 micromoles/L (14.7 micrograms/dL).[8]
Lead exposure in adults
The primary source of lead exposure is occupational (such as scraping off old lead paint, smelters, battery manufacturing, and radiator repair), rather than oral ingestion of lead-contaminated materials. Occupational exposures have, however, declined significantly in the US.[9]
Use of traditional folk medicines, such as Ayurvedic herbal remedies, has resulted in lead toxicity.[10][11]
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